Fiber reinforced aerogel insulation and method therefor

ABSTRACT

A method for producing an insulation product may include providing an aqueous solution. The aqueous solution may include coarse glass fibers, glass microfibers, aerogel particles, and a binder. The coarse glass fibers, the glass microfibers, the aerogel particles, and the binder may be uniformly dispersed in the aqueous solution and may form a slurry. The method may further include removing at least a portion of water from the slurry such that the coarse glass fibers, the glass microfibers, the aerogel particles, and the binder may form a wet laid mixture. The method may also include curing the wet laid mixture to cure the binder and bond the coarse glass fibers, the glass microfibers, and the aerogel particles together to form a fiberglass reinforced aerogel composite. The fiberglass reinforced aerogel composite may include between about 50 wt. % and about 75 wt. % of the aerogel particles.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/129,005 filed Sep. 12, 2018. This application is related to U.S.patent Ser. No. 10/612,717 entitled “SYSTEM AND METHOD FOR FIBERREINFORCED AEROGEL INSULATION” issued Apr. 7, 2020; U.S. PatentApplication entitled “SYSTEMS AND METHODS FOR INSULATING A PIPE WITH APRE-APPLIED VAPOR-BARRIER STOP” filed Sep. 12, 2018, U.S. applicationSer. No. 16/128,692; and U.S. Patent Application entitled “FIBERREINFORCED AEROGEL INSULATION” filed Sep. 12, 2018, U.S. applicationSer. No. 16/128,886. The entire disclosure of all of the aforementionedU.S. Patent Applications are hereby incorporated by reference, for allpurposes, as if fully set forth herein.

BACKGROUND OF THE INVENTION

This invention relates generally to insulation products. Morespecifically the invention relates to fiber reinforcedaerogel-containing insulation products.

BRIEF DESCRIPTION OF THE INVENTION

The embodiments described herein relate to fiber reinforced aerogelinsulation and method therefor. In some embodiments, a method forproducing a pipe insulation product may include providing an aqueoussolution. The aqueous solution may include coarse glass fibers, glassmicrofibers, aerogel particles, and a binder. The coarse glass fibersmay have an average fiber diameter between about 8 μm and about 20 μm.The glass microfibers may have an average fiber diameter between about0.5 μm and about 3 μm. The coarse glass fibers, the glass microfibers,the aerogel particles, and the binder may be uniformly dispersed in theaqueous solution and may form a slurry. The method may further includeremoving at least a portion of water from the slurry such that thecoarse glass fibers, the glass microfibers, the aerogel particles, andthe binder may form a wet laid mixture. The method may also includecuring the wet laid mixture to cure the binder and bond the coarse glassfibers, the glass microfibers, and the aerogel particles together toform a fiberglass reinforced aerogel composite. The fiberglassreinforced aerogel composite may include between about 50 wt. % andabout 75 wt. % of the aerogel particles.

In some embodiments, the method may further include forming a preformfrom the slurry and transferring the preform into a mold. In someembodiments, the wet laid mixture may be cured at a temperature betweenabout 350° F. to about 500° F. for a period of time between about 30minutes to about 3 hours.

In some embodiments, the method may further include trimming thefiberglass reinforced aerogel composite, collecting scraps of thefiberglass reinforced aerogel composite from the trimming operation, andgrinding the scraps of the fiberglass reinforced aerogel composite toproduce particles of the fiberglass reinforced aerogel composite. Theparticles produced may have a diameter of less than or about 0.13 inch.The method may further include mixing the particles of the fiberglassreinforced aerogel composite into the aqueous solution. A ratio of acombined weight of the coarse glass fibers, the glass microfibers, theaerogel particles, and the binder to a weight of the particles of thefiberglass reinforced aerogel composite is about 10:1 or greater. Insome embodiments, the method may further include removing, from theground fiberglass reinforced aerogel composite, clumps of the fiberglassreinforced aerogel composite having a diameter greater than about 0.1inch.

In some embodiments, the method may further include pouring the aqueoussolution onto a porous inner facer. The porous inner facer may include ascrim. In some embodiments, the method may further include applying avapor barrier to the fiberglass reinforced aerogel composite.

In some embodiments, the fiberglass reinforced aerogel compositeincludes about 3 wt. % of the coarse glass fibers and about 10 wt. % ofthe glass microfibers. The fiberglass reinforced aerogel composite mayhave a density of between about 6 pcf and about 8 pcf. An averagediameter of the aerogel particles may be between about 10 nm and about4.0 mm. The aerogel particles may include silica aerogel. The fiberglassreinforced aerogel composite may have a thickness of between about 1inch and about 1.25 inches.

In some embodiments, a method for producing an insulation product mayinclude providing an aqueous solution. The aqueous solution may includecoarse glass fibers, glass microfibers, aerogel particles, and a binder.The coarse glass fibers may have a first average fiber diameter. Theglass microfibers may have a second average fiber diameter less than thefirst average fiber diameter. The coarse glass fibers, the glassmicrofibers, the aerogel particles, and the binder may be uniformlydispersed in the aqueous solution and form a slurry. The method mayfurther include removing at least a portion of water from the slurrysuch that the coarse glass fibers, the glass microfibers, the aerogelparticles, and the binder form a wet laid mixture. The method mayfurther include curing the wet laid mixture to bond the coarse glassfibers, the glass microfibers, and the aerogel particles to form afiberglass reinforced aerogel composite.

In some embodiments, a ratio between a weight of the aerogel particlesand a combined weight of the coarse glass fibers and the glassmicrofibers may range between about 2:1 and about 5:1. A ratio of aweight of the coarse glass fibers to a weight of the glass microfibersmay be about 3:10. The fiberglass reinforced aerogel composite mayinclude between about 50 wt. % and about 75 wt. % of the aerogelparticles.

In some embodiments, the method may further include trimming thefiberglass reinforced aerogel composite, collecting scraps of thefiberglass reinforced aerogel composite from the trimming operation, andgrinding the scraps of the fiberglass reinforced aerogel composite toproduce particles of the fiberglass reinforced aerogel composite. Themethod may further include mixing the particles of the fiberglassreinforced aerogel composite into the aqueous solution. In someembodiments, a ratio of a combined weight of the coarse glass fibers,the glass microfibers, the aerogel particles, and the binder to a weightof the particles of the fiberglass reinforced aerogel composite may beabout 10:1 or greater.

In some embodiments, the fiberglass reinforced aerogel composite mayhave a density of between about 5.5 pcf and about 8 pcf. In someembodiments, a flexural strength of the fiberglass reinforced aerogelcomposite may be reduced by less than about 20% after submersion inliquid nitrogen.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described in conjunction with the appendedfigures:

FIGS. 1A and 1B schematically illustrate perspective views of a pipewith insulation product positioned about the pipe.

FIG. 1C illustrates a cross sectional view taken along line C-C of FIG.1B.

FIG. 1D schematically illustrates a perspective view of another pipewith insulation product positioned about the pipe.

FIG. 1E schematically illustrates a perspective view of one section ofinsulation product.

FIG. 2 schematically illustrates an exemplary system for forming aninsulation product.

FIG. 3 schematically illustrates an exemplary mold assembly for formingan insulation product.

FIG. 4 illustrates an exemplary method of forming an insulation product.

FIG. 5A schematically illustrates an exemplary insulation productincluding a fiber reinforced aerogel composite body that may be formedusing the system of FIG. 2 and/or the method of FIG. 4.

FIG. 5B schematically illustrates an enlarged view of a cross section ofthe fiber reinforced aerogel composite of FIG. 5A.

FIG. 6 schematically illustrates an exemplary system for forming fiberreinforced nonwoven aerogel mats.

FIG. 7 schematically illustrates an exemplary component that may be usedwith the system of FIG. 6 for forming fiber reinforced nonwoven aerogelmats.

FIG. 8 schematically illustrates an exemplary system for secondarilyprocessing fiber reinforced nonwoven aerogel mats.

FIG. 9 illustrates an exemplary method of secondarily processing fiberreinforced nonwoven aerogel mats.

In the appended figures, similar components and/or features may have thesame numerical reference label. Further, various components of the sametype may be distinguished by following the reference label by a letterthat distinguishes among the similar components and/or features. If onlythe first numerical reference label is used in the specification, thedescription is applicable to any one of the similar components and/orfeatures having the same first numerical reference label irrespective ofthe letter suffix.

DETAILED DESCRIPTION OF THE INVENTION

The ensuing description provides exemplary embodiments only, and is notintended to limit the scope, applicability or configuration of thedisclosure. Rather, the ensuing description of the exemplary embodimentswill provide those skilled in the art with an enabling description forimplementing one or more exemplary embodiments. It being understood thatvarious changes may be made in the function and arrangement of elementswithout departing from the spirit and scope of the invention as setforth in the appended claims.

“ASTM” refers to American Society for Testing and Materials and is usedto identify a test method by number. The year of the test method iseither identified by suffix following the test number or is the mostrecent test method prior to the priority date of this document.

Described below are various insulation products formed from aerogelparticles and reinforcing fibers. The various insulation products may bepre-applied with facers that not only improve structural and thermalproperties, but also allow for quick installation in the field. Theinsulation products offer excellent thermal performance for cryogenic,cold, or warm temperature applications, but can also be used for hightemperature applications.

FIGS. 1A and 1B illustrate perspective views of a portion of a pipe 100with one or more layers 102 of an insulation product positioned aboutthe pipe 100. In FIG. 1A, a section of the insulation product is shownin a partially disassembled state, and in FIG. 1B, the layers 102 areassembled around the pipe section 100. FIG. 1C illustrates a crosssectional view taken along line C-C of FIG. 1B. Although two insulationlayers 102, i.e., an inner layer 102 a of the insulation product and anouter layer 102 b of the insulation product, are shown, depending on theparticular application, the size and/or construction of the pipe 100and/or each layer 102 of the insulation product, more or fewer layers102 of the insulation product may be utilized.

The pipe 100 may be a cylindrical pipe or tubing having a longitudinalaxis 101. The pipe 100 may be made of suitable materials fortransporting fluids at relatively low temperatures. For example, thepipe 100 may transport fuel and/or chemicals, such as liquefied naturalgas, ethylene, ammonia, nitrogen, hydrogen, or other fluids in theirrespective liquid states, and thus at various temperatures within orbelow the refrigeration temperature range or the cryogenic temperaturerange, such as below about 100° F., below about 0° F., below about −100°F., below about −200° F., below about −300° F., below about −400° F., orlower. For example, the insulated pipe 100 may transport liquefiednatural gas at about −260° F., liquefied ethylene at about −155° F.,liquefied ammonia at about −28° F., etc. Although a straight section ofthe pipe 100 is shown, the entire pipe system for transporting thefluids may include fittings for connecting straight pipe sections and/orother components for regulating the flow of the fluids. As will bedescribed in more detail below, the insulation product may be preformedinto any suitable shapes and sizes, such as by molding and/or variousother manufacturing methods, such that layers or other shapes or formsof the insulation product may be installed onto pipe sections, fittings,and/or other components of the pipe system with minimal fabrication atthe installation site.

The layers 102 of the insulation product may each be formed as acylindrical body. Depending on the size and/or shape of the pipe 100,each layer 102 may be formed as a unitary or integral piece of theinsulation product or may be formed by joining multiple pieces orsections of the insulation product. When fewer number of pieces areinvolved in forming an insulation layer 102 surrounding the pipe 100 oran adjacent inner layer 102, the installation time may be reduced.However, as the size of the pipe 100 increases, the layers 102 of theinsulation product may be formed by joining multiple smaller piecestogether, such as shown in FIG. 1D. The smaller pieces can be moreefficiently stored and transported.

With reference to FIG. 1A, the inner layer 102 a may be formed as asingle or one-piece body, such a clamshell of two cylindrical halvesjoined by a hinge area. When installed onto the pipe 100, the clamshellcloses about the pipe 100. The abutting longitudinal edges of the twocylindrical halves may define a longitudinal seam or joint 104substantially parallel to the longitudinal axis 101 of the pipe 100. Thelongitudinal joint 104 may be sealed by sealants, adhesives, tapes, orany suitable sealing mechanism. The outer layer 102 b may be formed byjoining two separate cylindrical halves. FIG. 1A shows one of thecylindrical halves as positioned away from the nested inner layer 102 a.When fitted around the pipe 100, or more specifically, around the innerlayer 102 a as shown in FIG. 1B, the abutting longitudinal edges of thetwo cylindrical halves of the outer layer 102 b may form twolongitudinal seams or joints 106 substantially parallel to thelongitudinal axis 101 of the pipe 100, which may be sealed by sealants,adhesives, tapes, or any suitable sealing mechanism. In someembodiments, the inner layer 102 a may be formed by joining longitudinaledges of two separate cylindrical halves, instead of a one-piececlamshell structure. In some embodiments, the outer layer 102 b may beformed as a one-piece clamshell structure.

As can be seen from FIG. 1A, the longitudinal joints 106 of the outerlayer 102 b and the longitudinal joints 104 of the inner layer 102 a maybe rotationally offset from each other with respect to the longitudinalaxis 101 of the pipe 100, and thus not overlap. In the embodiment ofFIG. 1A, the longitudinal joints 106 of the outer layer 102 b may berotationally offset from the longitudinal joint 104 of the inner layer102 a by about 90 degrees. The longitudinal joints of adjacent layers102 may be offset by other appropriate angles in various embodiments.For example, the offset angle may be at least about ⅕, at least about ¼,at least about ⅓, or at least about ½ of the angle defined by thecircumferential extension of the insulation product pieces forming eachlayer 102, such as the cylindrical halves or sections of FIG. 1A or thecurved sections of FIG. 1D forming the outer layer 102 b as describedbelow.

FIG. 1A illustrates only one clamshell body of the inner layer 102 acovering a portion of the longitudinal extension of the pipe 100, butthe inner layer 102 a may include multiple clamshell bodies axiallyplaced along the longitudinal extension of the pipe 100 in an abuttingmanner. The abutting ends or edges of the clamshell bodies may formcircumferential seams or joints which may be sealed by sealants,adhesives, tapes, or any suitable sealing mechanism. Similarly, theouter layer 102 b may include additional cylindrical halves axiallyplaced along the longitudinal extension of the inner layer 102 a in anabutting manner. The abutting ends or edges of the cylindrical halvesmay form circumferential seams or joints which may be sealed bysealants, adhesives, tapes, or any suitable sealing mechanism.

As can be seen from FIG. 1A, the circumferential joints formed by thepieces of the outer layer 102 b may be offset from the circumferentialjoints formed by the pieces of the inner layer 102 a. In someembodiments, the upper cylindrical halves of the outer layer 102 b shownin FIG. 1A may be further axially offset from the lower cylindricalhalves. Consequently, the circumferential joints formed by the abuttingedges of the upper cylindrical halves may be also axially offset fromthe circumferential joints formed by the lower cylindrical halves. Insome embodiments, adjacent pairs of upper and lower cylindrical halvesof the outer layer 102 b may be rotationally offset from each other suchthat the longitudinal joints of adjacent pairs of upper and lowercylindrical halves may be rotationally offset from each other.Similarly, the adjacent clamshells of the insulation layer 102 may beplaced such that the longitudinal joints of the adjacent clamshells maybe rotationally offset from each other. The term circumferential orcircumference used herein may refer to the entire circular periphery ofthe pipe 100 or the insulation layer 102, or may refer to only a portionof the circular periphery of the pipe 100 or the insulation layers 102,such as an arc or a segment of the circular periphery as defined by theinsulation pieces forming the insulation layers 102. Further, the pipe100 and/or the insulation layer 102 may be cylindrical as shown in FIG.1A, but may be formed of any other suitable shapes, such as an oval orpolygonal shape. Accordingly, the term circumferential or circumferenceused herein may refer to the periphery, or portions thereof, of anyshape the pipe 100 or insulation layer 102 may be formed of, which mayinclude straight or curved peripheral portions.

As the size of the pipe 100 and/or the insulation layer 102 increases,the insulation layer 102 may be formed by joining multiple relativelysmall segments or sections of the insulation product as shown in FIG.1D. Although only two insulation layers 102, i.e., the inner layer 102 aand the outer layer 102 b are shown, more or less layers 102 may beimplemented. FIG. 1E illustrates one section 110 of the insulationproduct. The insulation product section 110 includes an inner surface112, an outer surface 114, two opposing longitudinal sides or ends 116,and two opposing circumferential sides or ends 118. The distance betweenthe inner surface 112 and the outer surface 114 defines a thickness T ofthe insulation product section 110. The distance between the twolongitudinal sides 116 defines a width W of the insulation productsection 110. The distance between the two circumferential sides 118defines a length L of the insulation product section 110.

The inner surface 112 and the outer surface 114 may be parallel to eachother, and thus define a uniform thickness T of the insulation productsection 110. The thickness T may range between about 0.5 inches andabout 2 inches, between 0.75 inches and about 1.5 inches, or betweenabout 1 inch and about 1.25 inches in various embodiments. Theinsulation product section 110 may also be made with a thickness Tgreater than 2 inches or less than 0.5 inches. The two circumferentialsides 118 of the insulation production section 110 may be parallel toeach other, and thus define a uniform length L of the insulation productsection 110. The insulation product section 110 may have a typicallength L of about 36 inches, but other length dimensions may be adopted.

Depending on the shape of the pipe section or components surrounded bythe insulation product section 110, the inner surface 112 and the outersurface 114 may include two curved surfaces each respectively forming aportion of one of two co-axially aligned cylindrical surfaces about thelongitudinal axis 101 of the pipe 100. The insulation product section110 may include a varying width W. For ease of discussion, the width Wof the insulation product section 110 may be defined as the arc lengthmeasured at the mid-point of the thickness T of the insulation productsection 110. The ratio of the length L to the width W of the insulationproduct section 110 may be at least about 1:1, at least about 1.5:1, atleast about 2:1, at least about 3:1, or greater, and the ratio of thewidth W to the thickness T of the insulation product section 110 may beat least about 1:1, at least about 2:1, at least about 3:1, at least4:1, at least about 5:1, at least about 6:1, or greater to effectivelyutilize storage space during transportation, while maintainingsufficient structural integrity of the insulation product sections 110for ease of handling during installation.

Similar to the embodiment shown in FIG. 1A, when joined together to formthe insulation layers 102, each insulation product section 110 may beaxially or rotationally offset from an adjacent insulation productsection 110. Consequently, the longitudinal joints formed by adjacentinsulation product sections 110 of one insulation layer 102 may berotationally offset from the longitudinal joints formed by adjacentinsulation product sections 110 of adjacent inner and/or outerinsulation layers 102, and the circumferential joints formed by adjacentinsulation product sections 110 of one insulation layer 102 may also beaxially offset from the circumferential joints formed by adjacentinsulation product sections 110 of adjacent inner and/or outerinsulation layers. The longitudinal and/or circumferential joints formedby the insulation product sections 110 within each insulation layer 102may be further offset from each other. The offset arrangement of theseams or joints minimizes or substantially prevents vapor condensationtravelling cross the layers 102.

As will be discussed in more detail below, the insulation product piecesforming the insulation layers 102, such as the clamshells, thecylindrical halves, or the cylindrical sections described herein, may bepre-fabricated with inner and/or outer facers. The inner facer mayinclude a woven or nonwoven layer, and the outer facer may include avapor barrier facer. The facers may improve the structural integrity ofthe insulation pieces and may minimize dust that may be generated duringtransportation and installation. The insulation pieces may furtherinclude joining or sealing tapes along the edges of the insulationpieces or other pre-applied adhesives that may be quickly activated inthe field. The pre-fabricated facers and sealing mechanisms allow forquick installation and reduce overall cost of the insulation system.

In the entire piping system, for every predetermined length of astraight pipe section, vapor barrier stops may be applied to prevent anymoisture trapped between the pipe 100 and the insulation layers 102 fromtravelling axially for an extended distance. FIG. 1D illustrates an endportion of one such predetermined length of the straight pipe section.At the end portion, the circumferential end of the inner layer 102 a andthe circumferential end of the outer layer 102 b may be axially offsetfrom each other with the circumferential end of the inner layer 102 aextending beyond the circumferential end of the outer layer 102 b. Avapor barrier stop may be applied along the stepped profile defined bythe pipe 100, the inner layer 102 a, and the outer layer 102 b. A morethorough or complete description of the vapor barrier stop is providedin Applicant's U.S. Patent No. 10,774,976 entitled “SYSTEMS AND METHODSFOR INSULATING A PIPE WITH A PRE-APPLIED VAPOR-BARRIER STOP”, which ispreviously incorporated by reference.

FIG. 2 schematically illustrates a system 200 for forming an insulationproduct that may be used to form insulation layers for pipes asdiscussed above with reference to FIGS. 1A-1E. The system 200 includes amixing chamber 202, such as a hydro pulper for mixing aerogel particles,reinforcing fibers, a binder, and various additives, including a waterrepellent additive, in an aqueous solution (also referred to aswhitewater) to form a slurry. Various mixing or blending techniques,including paddle wheel mixing, may be utilized. Vortex mixing may alsobe utilized to blend the ingredients together without being mechanicallyabusive to the ingredients, such as breaking the fibers into shorterlengths or grinding the aerogel into finer particles. In someembodiments, recycled insulation product particles may also be added tothe whitewater solution for forming the mixture as will be discussedbelow. To maintain the uniform or homogenous distribution of the variousingredients in the mixture, the mixture may be used soon after thedesired uniformity is achieved, such as within minutes, so that themixture does not begin to separate or settle and become non-uniform.

The whitewater may include surfactants and viscosity modifiers, similarto the whitewater used to manufacture nonwoven glass mats such asdescribed in U.S. Pat. No. 10,003,056, the entire disclosure of which ishereby incorporated by reference. The whitewater may facilitate the evendistribution of the ingredients in the slurry. The whitewater may be fedinto the mixing chamber 202 from a whitewater container 203, which maybe used to prepare the whitewater solution using in part recycledwhitewater as will be described in more detail below.

The aerogel particles are synthetic highly porous and ultralight weightmaterials. The aerogel particles are typically made through a sol-gelprocess, although any other process of forming the aerogel particlesknown in the art may be employed. The aerogel particles are excellentthermal insulators due to being extremely light weight, low density(i.e., 98% air), and having extremely small pore sizes, which typicallyare between 10 nm and 40 nm. The nano-sized pores of the aerogelparticles enable the aerogel particles to exhibit low thermalconductivity by essentially eliminating convection and gas conductionheat or thermal energy transfer. In some embodiments, the aerogelparticles used for making the insulation product may include hydrophobicsilica aerogel particles. In some embodiments, the aerogel particles mayalso include various other materials, such as organic aerogels,polyimide aerogel, polyurethane aerogel, and the like. A more thoroughor complete description of the aerogel particles is provided in U.S.patent application Ser. No. 15/804,834, the entire disclosure of whichis hereby incorporated by reference.

Depending on the applications, the formed insulation product may includebetween about 50 wt % and about 75 wt % of the aerogel particles in thefinished molded product. The aerogel particles may have a particle sizeor diameter between about 10 and 4,000 microns. In some embodiments, theaerogel particles used for forming the insulation product may have aparticle size or diameter between 25 and 500 microns, or between 50 and300 microns, or between 100 and 200 microns. Various other particlesizes for the aerogel particles may likewise be employed. A particlesize of between 100 and 200 microns may enable the aerogel particles tobe easily dispersed within a whitewater solution and allow the water tobe easily drained during the formation of the insulation product. Theaerogel particles may be hydrophobic, which enables the aerogelparticles to be directly added to water in the insulation productformation process without the water, or other materials in the water,plugging the pores of the aerogel particles. If the pores of the aerogelparticles are plugged, the desired insulative properties may be negatedor eliminated.

The reinforcing fibers may include organic or inorganic fibers. Theinorganic fibers improve fire resistance property of the insulationproduct. In some embodiments, the inorganic fibers may include glassfibers. The glass fibers may include a mixture of coarse glass fibersand glass microfibers. The coarse glass fibers may have an average fiberdiameter between about 8 microns and about 20 microns. The average fiberlength of the coarse glass fibers may range between about ¼ inches andabout 1 to about 1% inches. In some embodiments, wet chop E glass fibershaving an average fiber diameter of about 13 microns at about % inchlength may be used for the insulation product. The glass microfibers mayhave an average fiber diameter between about 0.5 microns and about 3microns. The length of the glass microfibers may range between about ⅛inches and about 6 inches, more typically between about ⅛ inches andabout 4 inches. In some embodiments, dry glass microfibers having anaverage fiber diameter of about 0.8 microns at about 20 microns lengthmay be used for the insulation product.

The mixture of the coarse glass fibers and glass microfibers used forforming the insulation product may have a ratio of the coarse glassfiber diameter to the glass microfiber diameter between 40:1 and between5:1, such as about 30:1, about 20:1, about 16.25:1, about 15:1, or about10:1 in various embodiments. Depending on the applications, theinsulation product may include between about 1 wt. % and about 6 wt. %of the coarse glass fibers, such as 3 wt. % of the coarse glass fibers,and include between about 5 wt. % and about 15 wt. % of the glassmicrofibers, such as 10 wt. % of the glass microfibers. The ratio of theweight of the coarse glass fibers in the formed insulation product tothe weight of the glass microfibers may range between about 2:3 andabout 1:3, such as about 3:10. Small additions of coarse fiber cansignificantly improve tensile and tear resistant in mats madepredominately with glass microfibers. Glass microfibers can forminterconnected webs or network that can hold or trap small particles,such as aerogel particles, in place. Although coarse glass fibers andglass microfibers are described as exemplary components of the glassfibers, the glass fibers may include only coarse glass fibers but notglass microfibers, or vice versa.

The binder may include a polysiloxane binder. To provide desired fireresistance for the finished product, fire resistant binders are used,such as high temperature binders or binders with low organic content,including polysiloxane. Other binders that are less fire resistant thatmay be used include polyacrylic, phenolic, polyethylene acrylatecopolymer, polyethylene vinyl acetate and polyvinyl alcohol. In someembodiments, the binder may further include a flocculating agent, suchas ferric nitride. The flocculating agent aggregates the binder andother liquid additives, or stated differently, agglomerates the micellesof binder and water repellent in the whitewater, so that they canaccumulate on solid surfaces of the fibers and aerogel particles. Thisway, the binder and/or other liquid additives remain on the solidsurfaces instead of passing or flowing through the mixture and into thewhitewater recycle tank. As shown below, the flocculating agent used canalso improve strength of the insulation product. One exemplaryflocculating agent may include ferric nitride because it is inorganic,which helps maintain product fire resistant, and it improves productstrength compared to Alum. Further, ferric nitride converts to ironoxide, which acts as an opacifier to block radiative heat transfer attemperatures above room temperature.

The water repellent additive may include a silicone emulsion to improvewater resistance of the insulation product. In some embodiments, thesilicon emulsion may include emulsions made with reactive silicon, suchas SF75 manufactured by Dow Corning. The reaction of the siliconeemulsion may be activated and/or facilitated by drying and elevatedtemperature curing to provide the desired water repellency for theinsulation product. In some embodiments, a fluoropolymer water repellentadditive may be used.

With continued reference to FIG. 2, once the aerogel particles, glassfibers, binder, and the various additives are mixed and form asubstantially homogenous mixture, the mixture is then transferred into adewatering box 204. The mixture may be dewatered by vacuum generated bya vacuum table 206 underneath the dewatering box 204. In someembodiments, the mixture may be dewatered through compression or bygravity. In some embodiments, the bottom of the dewatering box 204 maybe lined with a carrier layer 208, which may be then subsequently bondedto the mixture and form an inner facer of the finished insulationproduct. The carrier layer 208 may be omitted in some embodiments. Thecarrier layer 208 may include a woven or nonwoven material, such aspolyester, glass nonwoven, spunbond, scrim, or other suitable carriermaterials. The carrier layer 208 is porous such that excess water may beremoved in the subsequent dewatering and/or subsequent drying process.

Through the dewatering process, a substantial amount of the whitewatersolution may be removed. Because the insulation product may be designedfor cryogenic applications, and in the cryogenic temperature range, suchas below 75° F., black opacifiers, such as carbon black, offer limitedbenefits in the thermal properties of insulation products, theinsulation product may be made without carbon black or other blackopacifiers. By eliminating carbon black or other black opacifiers, aclosed loop whitewater system may be formed and the insulation productmay be manufactured more efficiently. Specifically, the liquid removedfrom the mixture through the dewatering process may be drained into awhitewater recycle trough 210 and collected and processed in awhitewater recycler 212. The recycled whitewater may then be reused.Depending on the particular dewatering process employed, a minimum of 50wt. % and as much as 90 wt. % of the liquid or process water may bereadjusted to the desired viscosity and surfactant concentration to addback into the whitewater tank and reused.

After the dewatering process, a blanket 212 of entangled fibers with theaerogel particles embedded therein, the binder, and other additivesuniformly distributed throughout the blanket 212 may be formed in thedewatering box 204. About 50 wt. % to about 66 wt. % of water may stillremain in the blanket 212. Because the aerogel particicles arehydrophobic, the residual whitewater and the wet binder contains theremaining water content in the blanket 212. The remaining water contentmay be removed during subsequent drying and/or curing process asdiscussed below.

Depending on the final form of the insulation product, the amount of theslurry mixture pumped into the dewatering box 204 may be controlled suchthat after dewatering, the blanket 212 formed may have a thicknessranging between about 1 inch to about 4 inches, and in some embodimentsabout 2 inches. The thickness of the blanket 212 may be reduced duringsubsequent molding process for forming the insulation product. Thedensity of the blanket 212 formed after the dewatering process may rangebetween about 7 pcf to 20 pcf, which may be increased during thesubsequent molding process. For example, during the molding process, a1.5″ thick dewatered blanket having a density of about 10 pcf may becompressed to about 1″ thickness. If no further water or whitewater issqueezed out of the dewatered blanket during the molding process, thedensity of the dewatered blanket may be increased to 15 pcf beforedrying and curing.

With continued reference to FIG. 2, once dewatered, the blanket 212 ofentangled fibers may be transferred to a mold assembly 220. In someembodiments, before transferring to the mold assembly 220, the blanket212 may be further cut into multiple sections 213 each of which would bemolded into an insulation product piece. The blanket 212 or the cutsections 213 may also be referred to as preforms. The mold assembly 220may include an upper mold member 222 and a lower mold member 224. Theupper mold member 222 may be moved by a mold press 225 upward ordownward relative to the lower mold member 224 to open and close themold assembly 220. The upper mold member 222 may include one or moreupper mold halves 226, each of which may take the form of a cylindricalhalf. The lower mold member 224 may include a corresponding number oflower mold halves 228, each of which may also take the form of acylindrical half. When the mold assembly 220 is closed, each of theupper mold half 226 is configured to operate with a corresponding lowermold half 228 to further compress and mold the blanket 212 or sections213 into the proper form of the insulation product, such as cylindricalhalves as illustrated in FIG. 2.

Although molds of a cylindrical shape are described herein as anexample, the molds may be formed by cooperating pieces that may definean arc greater than or less than a half circle. In some embodiments,instead of curved molding surfaces, the molding surfaces may be flat.FIG. 2 illustrates that the upper mold halves 226 and the lower moldhalves 228 are configured in a downward facing manner with the uppermold halves 226 having a greater inner diameter than the outer diameterof the lower mold halves 228. In some embodiments, the upper mold halves226 and the lower mold halves 228 may be configured in a generallyupward facing manner with the lower mold halves 228 having a greaterinner diameter than the outer diameter of the upper mold halves 226. Theupper and lower mold haves 226, 228 may include water drainage or vaporoutlets.

As discussed above, the preforms, or the blanket 212 or blanket sections213, may be obtained by using vacuum, compression, and/or gravity toremove excess water from the slurry mixture. Accordingly, the dewateringprocess may effectively pack the slurry mixture into a denser dampmixture, which provides structural integrity to the preforms. Theflocculating agent and/or the spunbond or other nonwoven carrier layer208, including nonwoven glass fiber mat, may also add structuralstrength to the preforms. With sufficient structural integrity, thepreforms may be molded into the various final forms of the insulationproduct without using a fully closed mold. For example, the moldassembly 220 is configured such that the side(s) or end(s) of each pairof mold halves may be left open, which may significantly reducedrying/curing time. Depending on the thickness of the insulationproducts, the molded blanket sections 213 and the mold assembly 220 maybe dried and cured in a drying oven 230 at about 350° F. to about 500°F. for as little as about 30 minutes to 3 hours to substantially removeall the remaining water content.

Because after dewatering, the preform may still contain about 50 wt. %or more of water content, the processing in the oven 230 may begin witha drying process. When the water evaporates and the binder is exposed totemperatures above about 100° C., the binder starts to cure to bond theentangled fibers and the embedded aerogel particles together. The binderalso bonds the carrier layer 208 to the inner or concave surface of theblanket sections 213. In some embodiments, a steam pressure autoclavemay be used to cure the binder while water is still in the preform.

During the drying and/or curing process, the water repellent additivedries and cures at the same time the binder dries and cures. The waterrepellent additive provides water repellency throughout the insulationproduct. However, because of the drying process occurs outside toinside, some water repellents may slightly wick into the drier portionof the insulation product, which may make the surface portion more waterrepellent that the inner insulation core.

When cured, the molded blanket sections 213 forms a molded aerogelinsulation product, which is a fiber reinforced aerogel composite orglass fiber reinforced aerogel composite in some examples. The moldedaerogel insulation product is then demolded and trimmed, and insulationproduct sections 232 are produced. In some embodiments, the insulationproduct sections 232 may each be fabricated with an outer facer or avapor barrier facer. The vapor barrier facer may be applied after theinsulation product sections 232 are molded. Alternatively, the vaporbarrier facer may be laid on the dewatered blanket 212 before it iscompressed and molded. The vapor barrier facer may be bonded to theouter or convex surface of the insulation product sections 232 by thebinder. The vapor barrier facer may include aluminum foil at a thicknessof about 0.001″ to about 0.005″. The inner spunbond or other nonwovenfacer and the outer vapor barrier facers may improve the structuralintegrity of the insulation pieces and/or minimize dust that may begenerated during packaging 240, transportation, and/or installation.

FIG. 3 illustrates an exemplary mold assembly 300 that may be used forforming an insulation product that may be used to form insulation layersfor pipes as discussed above with reference to FIGS. 1A-1E. The moldassembly 300 may be incorporated into the system shown in FIG. 2. Themold assembly 300 may include an upper mold half 302 and a lower moldhalf 304. The lower mold half 304 defines a mold cavity for receiving apreform of entangled fibers with aerogel particles embedded therein andbinder and other additives uniformly distributed throughout. The preformmay be the blanket 212 or blanket sections 213 as discussed above withreference to FIG. 2. When the upper mold half 302 and the lower moldhalf 304 are closed, the preform may be compressed and take the shape ofthe mold 300. The compressed preform may then be cured in an oven, suchas the oven 230 discussed above with reference to FIG. 2.

In some embodiments, instead of placing preforms, such as the blanket212 or blanket sections 213 into the mold assembly 300, a damp mixtureof reinforcing fibers, aerogel particles, binder, and/or additives,which may be obtained by dewatering the slurry mixture using adewatering box, may be placed or packed into the mold assembly 300. Thisprovides the flexibility in selecting a dewatering equipment. In someembodiments, the lower mold half 304 may be configured with drainageholes 306 at the bottom of the lower mold half 304 such that excesswater in the slurry mixture may be drained before being cured. AlthoughFIG. 3 illustrates a mold assembly 300 defining a cavity of acylindrical half. Other mold cavity configuration may be utilized forproducing curved or flat sections of the insulation product. In someembodiments, the mold may be a clamshell mold and thus produces fullcylindrical or two connected cylindrical halves. Further, although onlyone mold assembly 300 is illustrated in FIG. 3, multiple mold assemblies300 may be arranged in an array similar to the mold assembly 220 shownin FIG. 2 for manufacturing multiple insulation product sectionssimultaneously.

As discussed above, the fiber reinforced aerogel composite insulationproduct may be molded from preforms of entangled fibers with aerogelparticles, binder, and other additives embedded therein, which offerexcellent finished product strength. Alternatively, the fiber reinforcedaerogel composite insulation product may be molded by packing thedewatered mixture of entangled fibers, aerogel particles, binder, and/orother additives into molds of any shapes. This may be achieved bybreaking the entanged mixture into smaller pieces, if needed, and packthe smaller pieces into the molds. The fiber reinforced aerogelcomposite insulation product formed by the alternative packing methodallows insulation products of complex shapes including elbows and teesto be made by molding while still offers sufficient product strength.

Referring now to FIG. 4, illustrated is a method 400 of forming aninsulation product that may be used to form insulation layers for pipesas discussed above with reference to FIGS. 1A-1E. The method may beperformed using all or some components of the system 200 described abovewith reference to FIG. 2. At block 405, an aqueous solution is prepared.The aqueous solution may include whitewater, which may further includerecycled whitewater if a closed loop whitewater system is implemented asdiscussed above with reference to FIG. 2. At block 410, aerogelparticles, fibers, binder materials, and various additives are mixedtogether in the whitewater solution so that the aerogel particles, thefibers, the binder and the additives are uniformly dispersed in thewhitewater solution to form a homogenous slurry or mixture. At block415, the homogenous mixture is dewatered using gravity, compression,vacuum, and/or other dewatering techniques. The water content removedincludes whitewater that may be collected and recycled at block 420. Atblock 425, the dewatered mixture is transferred into a mold assemblythat defines the shape of the finished insulation product. In someembodiments, the mixture may be dewatered over a carrier layer, such asa spunbond nonwoven material, which may also be transferred into themold assembly and subsequently forms an inner facer of the finishedinsulation product. At block 430, the dewatered mixture, while beingheld in the mold, is dried to remove excess water content and the binderin the mixture is cured in an oven. The drying process may take placefirst as the temperature of the molded mixture increase. The curingprocess may be performed at a temperature between about 350° F. to about500° F. for a period of time between about 30 minutes to about 3 hours.Once dried and cured, the molded product is demolded and cooled at block435. At block 440, end trimming, surface grind, and/or cleaning of themolded product may be performed, if necessary. In some embodiments,depending on the applications, the method 400 may further includeapplying an outer facer, such as a vapor barrier facer, to the outersurface of the insulation product at block 445. At block 445, a joiningor sealing tape or other adhesives may also be applied along the edge ofthe outer facer to facilitate joining adjacent insulation product piecestogether. At block 450, the finished insulation product pieces arepackaged.

In some embodiments, the method 400 of FIG. 4 may include additionalsteps that enable recycling insulation product that is trimmed orscrapped due to blemishes or other minor defects. Specifically, at block455, trimmed scraps may be collected, and at block 460, the collectedscraps may be ground up, screened and refeed into the manufacturingprocess. A ratio of new ingredients to the recycled content, which isalso referred to as refeed, ranges about 10:1, 15:1, 20:1, 25:1, orgreater. In some embodiments, up to 5 wt. % refeed may be included inthe formed insulation product that offers excellent structural andinsulation properties. In some embodiments, the scraps may be shreddedor lightly ground to create small pieces or particles having a diameterless than about 0.15 inches, less than about 0.13 inches, less thanabout 0.1 inches, or less. At block 465, the shredded/ground particlesmay be further screened to remove any larger chunks and/or clumps offiber reinforced aerogel composite having a diameter greater than orabout 0.1 inches. The removed clumps may include clumps of the glassfibers, also referred to as bird-nests of glass fibers, which may beformed by agglomerated glass fibers that may be difficult to breakapart. The glass fibers that form the clumps or bird-nests may be aslong as about 2 to 4 times the clump diameter. Once the scraps areground and screened, the particles may then be refed and used as a drybatch material.

FIG. 5A illustrates an insulation product 500 that may be made using thesystem 200 of FIG. 2 and/or method of FIG. 4 described above. Theinsulation product 500 illustrated is a cylindrical half, but may takeor be molded into any suitable form. The insulation product 500 includesa fiber reinforced aerogel composite body 502, an inner facer 504attached to an inner surface of the fiber reinforced aerogel compositebody 502, and an outer facer 506 attached to an outter surface of thefiber reinforced aerogel composite body 502. The inner facer 504generally includes a spunbond, a scrim, or other woven or nonwovenporous layer and/or material. The outer facer 506 may include a vaporretarder facer, such as ASJ-4535 facing, which is a flame-retardantvapor barrier facing manufactured by Johns Manville, or CustomLaminating 8923 vapor barrier manufactured by Custom LaminatingCorporation. The inner facer 504 and/or the outer facer 506 improve thestructural integrity of the insulation product 500, and reduce dustgenerated during transportaion and/or installation. The outer vaporbarrier facer 506 also limits vapor transfer between layers of theinsulation products 500 when multiple nested layers of the insulationproducts 500 are installed to achieve desired insulation result.However, the insulation product 500 may be manufactured without theinner facer 504 and/or the outer facer 506, because the insulationproduct 500 may possess sufficient structural interity to maintain itsshape during storage, transporation and/or installation. A vapor barrierlayer or material may be applied when the insulation products 500 areinstalled in the field.

In some embodiments, the outer facer 506 may extend beyond alongitudinal edge of the outer surface of the fiber reinforced aerogelcomposite body 502, and a sealing mechanism, such as a sealing tape 508,may be applied at the extension of the outer facer 506 on the side ofthe extension facing the fluid pipe or container or another nestedinsulation layer. The sealing tape 508 may be included if the insulationproduct 500 is in a pipe or cylinder form, such as a clamshell body. Thetape 508 may be included along the longitudinal edge of one of the twocylindrical halves of the clamshell body. When the insulation product500 is placed about the pipe or container to be insulated, the tape 508may be adhered to the other surface of the other of the two cylindricalhalves of the clamshell body to close the longitudinal joint/seam formedby the abutting edges of the two adjacent pieces. In some embodiments,insulation products 500 in the form of cylindrical halves or smallerpieces, flat or curved, may also include a sealing tape that may joinand seal the longitudinal joints/seams of adjacent pieces. Lateral vaportransfer may occur at the interface between the sealing tape and theinsulation facer where certain types of pressure sensitive adhesives orless than smooth surface substrates may allow vapor to move within thatinterface. To limit or substantially eliminate lateral vapor transfer,wider tapes are often used to minimize the lateral vapor transfer bymaking the vapor path length longer. In some embodiments, the width ofthe tape 508, as measured along the extension of the outer facer 506beyond the fiber reinforced aerogel composite body 502, may be at least1 inch, at least 1.5 inches, at least 2 inches, or more in variousembodiments depending on the thickness of the insulation layer installedand other factors. For example, when multiple insulation layers areinstalled with each layer having a thickness of about 1.0 to 1.25inches, the width of the sealing tape 508 may be at least 1.5 inches ormore to minimize or substantially eliminate lateral vapor transferacross taped joints. To further limit vapor transfer, thecircumferential joints/seams between adjacent insulation products 500may also be sealed with tapes, such as 3M™ Venture Taper™, CryogenicVapor Barrier Tape 1555CW, or other sealing mechanisms.

The fiber reinforced aerogel composite body 502 may include a thicknessdefined as the distance between the inner and outer surfaces of thefiber reinforced aerogel composite body 502. The thickness may rangebetween about 0.5 inches and about 2 inches, between 0.75 inches andabout 1.5 inches, or between about 1 inch and about 1.25 inches invarious embodiments. The insulation product 500 may also be made with athickness greater than 2 inches or less than 0.5 inches. Depending onthe applications, a single layer or multiple layers of the insulationproduct 500 may be utilized to achieve desired insulation performance.When the fiber reinforced aerogel composite body 502 is formed with arelatively smaller thickness, the insulation product 500 may be flexibleenough to be wrapped around surfaces to be insulated, such as curvedsurfaces of relatively large diameters. For example, the insulationproduct 500 may be molded as a flat material at a thicknesses of about10 mm or less at a density of about 6.5 pcf. The insulation product 500may be flexible enough to be wrapped around pipes with diameters greaterthan about 12 inches. Consequently, to provide insulation to largecontainers, flat sheets or rolls of the insulation product may beproduced and provided to contractors for on-site fabrication andinsulation around large pipes, tanks and complex shapes to be insulated.The insulation sheets may be faced on the inner surface with alightweight carrier nonwoven such as 18-20 gsm polyester or similarnonwoven and faced on the outer side with the Custom Laminating 8923vapor barrier manufactured by Custom Laminating Corporation.

FIG. 5B illustrates an enlarged view of a cross section of the fiberreinforced aerogel composite body 502 of FIG. 5A in greater detail. Thefiber reinforced aerogel composite body 502 includes a network ofentangled fibers 510 with aerogel particles 512 embedded in the fibernetwork. As illustrated, the entangled fibers are randomly oriented, orin other words, the fiber orientation is in all directions. As discussedabove, the entanged fibers 510 may include one or more types of fibers,such as glass fibers, polymeric fibers, and the like. Each type of thefibers included in the fiber reinforced aerogel composite body 502 mayfurther vary in sizes, such as being made of different lengths and/ordiameters. In some embodiments, the entangled fibers 510 may include acombination of entangled coarse glass fibers 510 a having average fiberdiameters greater than 6 microns and glass microfibers 510 b havingaverage fiber diameters of less than 6 microns. The entangled fibersdefine a network within which the aerogel particles 512 are uniformlydispersed throughout. Although not explicitly illustrated, the curedbinder and other additives are also uniformly distributed throughout thefiber network. The binder bonds the entangled fibers 510, the aerogelparticles 512, and/or the various other additives together to form thefiber reinforced aerogel composite body 502. The random or all-directionorientation of the entangled fibers 510 and the uniform dispersion ofthe aerogel particles 512, the binder and/or the additives throughoutthe fiber network is achieved by mixing the ingredients in thewhitewater solution to form a homogenous mixture and by dewatering themixture soon after the homogenous mixture is formed so as to prevent theingredients from settling or separating and creating non uniformity inthe dewatered mixture.

Depending on the applications, the molded finished fiber reinforcedaerogel composite may include between about 50 wt % and about 75 wt % ofthe aerogel particles, between about 5 wt % and about 20 wt % of thebinder, between about 1 wt. % and about 6 wt. % of the coarse glassfibers, between about 5 wt. % and about 15 wt. % of the glassmicrofibers, and between about 0.01 wt. % and about 5 wt. % additives,such as water repellant additives. A ratio of the weight of the aerogelparticles to the combined weight of the coarse glass fibers and theglass microfibers ranges between about 2:1 and about 5:1. A ratio of theweight of the coarse glass fibers to the weight of the glass microfibersranges about 1:3 to 2:3, such as 3:10. Exemplary compositions of thefiber reinforced aerogel composite made according to the methoddescribed herein, such as the fiber reinforced aerogel composite body502 or the insulation product 500 without facers, are shown in Table 1and Table 2. The fiber reinforced aerogel composites shown in Table 1and Table 2 are composed mainly of aerogel particles and do not includeany black opacifiers.

TABLE 1 Fiber Reinforced Aerogel Composite with 65 wt.% Aerogel Content.% by weight Components (dry) Aerogel Particle (e.g., Aerogel P400 byCabot Corp.) 65 Microfiber (e.g., Microfiber 481 (210×) by 15 JohnsManville) Coarse fiber (e.g., Chopped Strand E-Glass by 10 JohnsManville) Binder (e.g., Polon MF-56 by Shin-Etsu 9.44 Silicones ofAmerica) Hydrophobic Agent (e.g., SF 75 by Dow Corning) 0.66

TABLE 2 Fiber Reinforced Aerogel Composite with 70 wt. % AerogelContent. % by weight Components (dry) Aerogel Particle (e.g., AerogelP400 by Cabot Corp.) 70 Microfiber (e.g., Microfiber 481 (210×) by 10Johns Manville) Coarse fiber (e.g., Chopped Strand E-Glass by 3 JohnsManville) Binder (e.g., Polon MF-56 by Shin-Etsu 15 Silicones ofAmerica) Hydrophobic Agent (e.g., SF 75 by Dow Corning) 2

The higher aerogel content of the fiber reinforced aerogel compositeshown in Table 2 creates a fiber-aerogel network that is more closely ortightly packed than the fiber reinforced aerogel composite shown inTable 1. This tighter packing provides an insulation product that hasincreased integrity and less dust. The tighter packing may be due to thefact that adding about 5% more light density aerogel (i.e., lighter thanthe other components in the composite) fills more void spaces in theinsulation. Fewer void spaces relates to fewer areas wheremoisture/water can accumulate. Fewer void spaces also relates to fewerweak points in the insulation.

Depending on the composition of the fiber reinforced aerogel compositeand/or the pressure applied by the mold holding the composite during thedrying/curing process, the finished molded fiber reinforced aerogelcomposite, in curved section form or flat board form, typically has adensity of between about 5.5 pcf and about 8 pcf. This density rangebalances product integrity/strength and cost and offers commerciallyviability for various insulation applications. Table 3 lists thedensities of various fiber reinforced aerogel composite samples withdifferent aerogel particle content. Finished products with higherdensity of up to about 12 pcf have been produced using the methoddescribed herein. Light weight products with a density as low as orbelow 5.5 pcf may be faced on the interior with a porous inner facerand/or on the exterior with a vapor barrier facer to deliver goodinsulation property as well as structural strength.

TABLE 3 Densities of Select Fiber Reinforced Aerogel Composites. Aerogel% by weight (dry) Density (pcf) 70 7.8 70 6.5 65 6.5 65 7.5 60 7.0

Compared to conventional insulation products that use aerogel, the fiberreinforced aerogel composites produced using the methods describedherein can be made using less amount of aerogel particles, which istypically the most expensive component, while still offers comparable oreven better insulation property and/or structural strength. Because lessaerogel particles are used, the fiber reinforced aerogel composites aremuch stronger and have or generate less dust because the microfibernetwork effectively holds a majority of the aerogel particles in place.The fiber reinforced aerogel composites are also more cost effectivethan conventional insulation products that use aerogel.

Table 4 lists the flexural strength breaking load of various fiberreinforced aerogel composite samples. Flexural strength is generallytested per ASTM C203. The test results were obtained based on a modifiedASTM C203 test so as to use 1 inch×1 inch×4 inches samples. Samples #1,#2, and #3 contains about 70% wt. % aerogel particles of the finishedfiber reinforced aerogel composites, and sample #4 contains about 65 wt.% aerogel particles of the finished fiber reinforced aerogel composite.Samples #1, #3, and #4 use ferric nitride as the flocculant, and sample#2 uses Alum (a hydrated double sulfate of aluminum and potassium) asthe flocculant, although other flocculants may be used. Generally, thehigher the density of the fiber reinforced aerogel composite, thegreater the flexural strength the fiber reinforced aerogel compositepossesses. The fiber reinforced aerogel composite also possessesexcellent flexural strength under cold or cryogenic temperatures. Thebreaking load of the fiber reinforced aerogel composite after submersionin liquid nitrogen is reduced by no more than 20%, or no more than 15%in some embodiments as compared to the breaking load measured withoutliquid nitrogen submersion.

TABLE 4 Flexural Strength Breaking Load of Select Fiber ReinforcedAerogel Composites. Max Load gF Aerogel Density Max Load (avg) After LN₂Sample ID wt. % (pcf) gF (avg) submersion # 1 - 70% 7 pcf Fe(NO₃)₃ 70%6.90 2103 1812 # 2 - 70% 7 pcf Alum 70% 6.60 1818 1535 # 3 - 70% 7 pcfFe(NO₃)₃ 70% 7.10 1776 — Hand Packed # 4 - 65% 7 pcf Fe(NO₃)₃ 65% 6.612685 —

As discussed above, the fiber reinforced aerogel composite may be moldedfrom a preform formed by dewatering the homogenous mixture of fibers,aerogel particles, binder, additives, etc. on a porous carrier layer.Alternatively, the fiber reinforced aerogel composite may be molded bypacking the dewatered mixture into the mold. Breaking the dewateredmixture into loose clumps may be involved in the alternative process topack the dewatered mixture into molds of complex shapes, which may yielda molded insulation product with slightly reduced flexural strength.Generally, the reduction in flexural strength may be less than about20%, less than about 15%, less than about 10%, less than about 5%, ascompared to insulation products formed from preforms with similarcomposition and/or density. Samples #1, #2, and #4 listed in Table 4were molded from preforms, and sample #3 was formed by breaking andpacking the dewatered mixture into a mold.

Table 4, as well as Table 5 below, illustrates that variables, such asinsulation density, aerogel content, flocculating agent type, and/orusing hand packed or dewatered blanket can be selected to achievedesired insulation properties. For example, about 70% aerogel content atabout 7 pcf density with ferric nitride as the flocculent may beselected for manufacturing an insulation product. Other factors, such asease of blending, ease of dewatering, finishing and cutting the finishedproduct may also be considered in selecting this and other desiredcompositions.

Table 5 lists the load strain at different compression percentages ofvarious fiber reinforced aerogel composite samples, tested in accordancewith ASTM C165.

TABLE 5 Load Strain of Select Fiber Reinforced Aerogel Composites. LoadStrain (lbf) Sample #3 Sample #1 Sample #2 70% 7 pcf Sample #4 % 70% 7pcf 70% 7 pcf Fe(NO₃)₃ 65% 7 pcf Compressed Fe(NO₃)₃ Alum Hand PackedFe(NO₃)₃ 5 201.48 150.74 604.68 589.95 10 359.48 296.10 728.18 724.08 15480.32 414.33 872.55 884.83 25 637.54 1267.82 1329.70

The fiber reinforced aerogel composites further possess excellentthermal insulation properties. The fiber reinforced aerogel compositesdescribed herein demonstrates improved thermal performance as comparedto conventional pipe insulation materials, such as cellular glass orpolyisocyanurate insulation rigid (PIR) foam. For example, the fiberreinforced aerogel composites that include about 60 wt. % to 70 wt. %aerogel particles and densities between 6.5 pcf to 8 pcf may have athermal conductivity of about 10 to 12 mW/m-K at about −250° F. to about−150° F., a thermal conductivity of about 12 to 18 mW/m-K at about −150°F. to about 50° F., a thermal conductivity of about 18 to 20 mW/m-K atabout 50 to 100° F., and a thermal conductivity of about 20 to 35 mW/m-Kat about 100 to 400° F., tested in accordance with ASTM C518. Incontrast, conventional cellular glass pipe insulation products may havea thermal conductivity that is at least twice the thermal conductivityof the fiber reinforced aerogel composites described herein. Forexample, conventional cellular glass pipe insulation typically have athermal conductivity of about 22 to 25 mW/m-k at about −250° F. to −150°F., a thermal conductivity of about 25 to 40 at about −150 to 50° F., athermal conductivity of about 40 to 45 mW/m-K at about 50 to 100° F.,and a thermal conductivity of about 45 to 80 mW/m-K at about 100 to 400°F.

Another way to evaluate an insulation material's thermal performance isthe k factor. Usually, insulation materials have a k factor of less thanone, and the lower the k factor, the better the insulation. The fiberreinforced aerogel composites described herein typically have a k factorof about 0.07 at about −270° F., about 0.1 at about −50° F., about 0.15at about 200° F., and about 0.25 at about 400° F. At highertemperatures, the k factor for the fiber reinforced aerogel compositesdescribed herein may increase from 0.25 at about 400° F. to about 0.5 atabout 700° F. Conventional cellular glass insulation products may have ak factor of about 0.16 at about −270° F., about 0.23 at about −50° F.,about 0.3 at about 200° F., and about 0.5 at about 400° F. At highertemperatures, the k factor for conventional cellular glass insulationproducts may increase from about 0.5 at about 400° F. to 0.75 at about700° F.

Given its improved insulation properties as compared to conventionalcellular glass or polyisocyanurate insulation rigid (PIR) foaminsulation products, the fiber reinforced aerogel composites describedherein can achieve equivalent thermal performance with reducedthickness. For example, to insulate a pipe having a 12-inch innerdiameter for transporting liquefied natural gas at −170° C. with theenvironmental temperature being about 23° C., a total thickness of about110 mm of cellular glass insulation material or a total thickness ofabout 100 mm polyisocyanurate insulation rigid (PIR) foam may be neededto achieve a heat flow of 36.6 or 33.1, respectively, as measured perunit length of the pipe, in btu/hr-ft. To insulate the same pipe, atotal thickness of only about 50 mm of the fiber reinforced aerogelcomposite described herein can achieve a heat flow of 32.6 btu/hr-ft perunit length of pipe. When a reduced thickness of insulation product isused, a smaller outer diameter of the insulated pipes may be achieved,which allows for closer arrangement of multiple pipes and also reducesthe size of protective cladding to cover the insulated pipe.

The thermal performance the fiber reinforced aerogel composites possessmay be further improved by increasing the content of aerogel particlesin the fiber reinforced aerogel composites. For example, by increasingthe aerogel particle content from 60 wt. % to 70 wt. %, the thermalconductivity of the fiber reinforced aerogel composite may be decreasedfrom about 12 mW/m-K to about 10 mW/m-K at about −238° F., decreasedfrom about 14.5 mW/m-K to about 12.5 mW/m-K at about 150° F., decreasedfrom about 17 mW/m-K to about 15 mW/m-K at about −50° F., decreased fromabout 19 mW/m-K to about 16.5 mW/m-K at about 32° F., and decreased fromabout 20.5 mW/m-K to about 18 mW/m-K at about 75° F. The thermalperformance of the fiber reinforced aerogel composites may be furtherimproved by increasing the densities of the molded product. For example,for molded fiber reinforced aerogel composites that contains similaraerogel particle content, increasing the density by about 10% may leadto at least about 5%, about 7%, or greater reduction in thermalconductivity.

The fiber reinforced aerogel composite described herein also improvesmanufacture and installation efficiency. The cellular glass andpolyisocyanurate insulation rigid (PIR) foam insulation products aretypically produced as blocks that are then cut and fabricated intosmaller pieces. Fixing the smaller pieces onto a pipe in the field canbe labor intensive because the insulation system typically involves twoto three insulation layers, an outer primary vapor barrier, anintermediate vapor barrier between the insulation layers, vapor stops,and a weather protective metal layer of cladding, such as 0.016″aluminum, 0.010″ stainless steel, or a nonmetallic cladding such asInsulSeal 50 manufactured by Protecto Wrap. In contrast, vapor barrierfacers and sealant tapes may be applied to the exterior of the fiberreinforced aerogel composite during fabrication, which facilitatesinstallation in the field. Additionally, cellular glass andpolyisocyanurate insulation rigid (PIR) foam insulation are relativelyrigid and thus require expansion joints. In contrast, the fiberreinforced aerogel composites described herein possess certain degree offlexibility and exhibit relatively low coefficient of thermal expansion(CTE), and thus may be installed for many cryogenic applications withoutexpansion joints.

Further, an asphalt coating is typically used between layers of cellularglass insulation because cellular glass insulation is relatively brittleand abrasive, and the pipes expand and contract frequently. The asphaltlayer keeps the insulation layers from wearing each other down andcreating dust. Instead of using an asphalt coating, the pre-appliedfacer for the fiber reinforced aerogel composites serves as the lowfriction expansion/contraction interface between the insulation layers.In addition, the pre-applied facers for the fiber reinforced aerogelcomposite described herein reduces dust that may be generated duringhandling and installation, and thus pose less health risk to the workersat the fabrication shop and in the field. Eliminating the asphaltcoating not only eliminates a fabrication step and the associated costs,but also eliminates the combustible asphalt from the insulation system.

Some conventional insulation product that contains aerogel, such aerogelcontaining blankets, may achieve similar insulation performance. Forexample, a total thickness of 50 mm of certain existing aerogel blanketsmay achieve a heat flow of about 34.5 btu/hr-ft per unit length of pipe.However, conventional aerogel blankets are typically manufactured in aflexible blanket form that has a thickness of about 5 mm or about 10 mmwith a thickness tolerance of about ±1 mm. To achieve a total thicknessof 50 mm or greater for the desired cryogenic thermal performance, theaerogel blanket needs to be wrapped around a pipe five, ten, or moretimes, which can create a problem for the contractor duringinstallation. Specifically, when wrapping five layers of the aerogelblanket that is 9 mm thick (i.e., 10 mm design-1 mm tolerance) insteadof 10 mm thick per design, the total insulation thickness is 45 mm. Ifthe adjacent section is insulated with another roll of the aerogelblanket that is 11 mm thick (i.e., 10 mm design+1 mm tolerance), thenthe total insulation thickness would be 55 mm. This 45 mm to 55 mm totalinsulation thickness difference creates a problem from both a visual andperformance standpoint which is unacceptable to the end customer. Incontrast, the fiber reinforced aerogel composite described herein can bemolded in pipe form and ready to be installed with minimal fabricationin the field. The fiber reinforced aerogel composite may be molded to athickness of about 25 mm to about 32 mm (or about 1 to about 1.25inches) with a thickness tolerance of ±1 mm, which leads to much lessvariation on the final insulation thickness around the pipe thanconventional aerogel blankets. Therefore, the fiber reinforced aerogelcomposite described herein improves system thickness control as comparedto conventional aerogel blankets. Further, dust from the fiberreinforced aerogel composite described herein is less than conventionalaerogel blankets. Even if some dust may be generated during handling,the dust from the fiber reinforced aerogel composite described hereingenerally falls to the floor whereas dust from conventional aerogelblanket floats in the air and gets on everything and all over theinsulation contractors.

The fiber reinforced aerogel composites described herein can also bemore cost effective as compared to conventional aerogel blankets.Conventional aerogel blankets are typically manufactured through acarefully controlled sol-gel process to form aerogel around apolyethylene (PE) fiber network. The fiber reinforced aerogel compositedescribed herein is molded using already formed aerogel particles.Conventional aerogel blankets typically includes about 90 wt. % to about95 wt. % aerogel content, which is typically the most expensivecomponent of the insulation product. The fiber reinforced aerogelcomposites described herein include about 60 wt. % to about 70 wt. %aerogel particles. By using already formed aerogel particles and a loweraerogel content in the final composite, the manufacturing costassociated with the fiber reinforced aerogel composite described hereincan be less. Additionally, because conventional aerogel blankets includea higher content of aerogel, the density of a typical aerogel blanket isat least 40% higher than that of the fiber reinforced aerogel compositedescribed herein. The fiber reinforced aerogel composite may also haveimproved fire resistance by using glass fibers.

Table 6 below lists additional properties of select fiber reinforcedaerogel composite samples that have different densities, as measuredaccording to various ASTM test methods when applicable. The fiberreinforced aerogel composite provides an FS/SD (flame spread/smokedevelopment) rating of 25/50, 5/30, or less, as measured according toASTM E-84 test. The insulation product further exhibits low coefficientof thermal expansion (CTE). For example, for the fiber reinforcedaerogel composite that includes about 65 wt. % of the aerogel particles,the CTE of the composite within the temperature range of 25 to 300° C.is about 11.0×10⁻⁶/K, and the CTE of the composite within thetemperature range of −150 to 25° C. is about 12.1×10⁻⁶/K. The fiberreinforced aerogel composite also possesses the properties of low soakwater retention, low water vapor sorption, and low water vaporpermeability. The insulation product 500 minimizes or substantiallyeliminates the corrosion on steel or other metal and/or alloys.

TABLE 6 Properties of Fiber Reinforced Aerogel Composite with 65 wt. %Aerogel. Property ASTM Test Sample #1 Sample #2 Aerogel Content (wt. %)65 wt. % 65 wt. % Typical Thickness (inches) 0.5-1.5 0.5-1.5 TypicalLength/Width (inches)  36  36 Max Use Temp. (F) 900 900 Min Use Temp.(F) <−297     <−297     Density (pcf) C167  7.5 6.4-6.7 ThermalConductivity (flat) − C177/C518 (C mean)(W/m-K) Mean Temp. (° C.)   2040.034 0.034   149 0.027 0.027    93 0.024 0.024    38 0.020 0.020    240.019 0.019    10 0.018 0.018  −18 0.017  0.017*  −50 0.016 0.016 −1000.014 0.014 −150 0.011 0.011 Flame Spread/Smoke E84 5/30 — Developed MaxWater Retention Max (wt. %) C1511 15 minutes submersion 13 wt. % — 24hour submersion 32 wt. % — Corrosion C871 Pass Pass C692 Pass Pass C1617Pass Pass Water Vapor Sorption C240, C1104  3 wt. % 3 wt. % Water VaporPermeability E96 >10 >10 Coeff. of Thermal Expansion E288 11.0 × 10⁻⁶/K— 25 to 300° C. Coeff. of Thermal Expansion E288 12.1 × 10⁻⁶/K — −150 to25° C. *Estimated value.

Because the fiber reinforced aerogel composite can be made without blackopacifiers and thus has higher aerogel content, the fiber reinforcedaerogel composite has excellent thermal performance for cryogenic, cold,or warm temperature applications from about −300° F. to about 400° F.For optimized performance at a minimal thickness at use temperaturesabove or about 75° F., the fiber reinforced aerogel composites mayinclude additives that block or reduce infrared radiation, such as TiO2,carbon black, iron oxide, high boron content glass fibers, or similarmaterials, including use of ferric nitride which may be used as aflocculant in some embodiments and convert to iron oxide which acts asan opacifier to block radiative heat transfer at temperatures above roomtemperature. The fiber reinforced aerogel composites described hereinretains the majority of its strength and integrity after 100 hours of1000° F. exposure. With added infrared radiation blocking materials, thefiber reinforced aerogel composites described herein can be used forinsulation at elevated temperatures of up to about 900° F.

FIG. 6 schematically illustrates a system 600 for forming a fiberreinforced nonwoven aerogel mat. The system 600 implements a wet laidnonwoven process. The system 600 includes a mixing chamber 602 withinwhich whitewater solution, aerogel particles, and fibers may be mixedtogether using various mixing techniques, such as vortex mixing, to forma uniform slurry mixture or suspension of entangled fiber network andaerogel particles dispersed throughout. Vortex mixing can blend theingredients together without being mechanically abusive to theingredients, such as breaking the fibers into shorter lengths orgrinding the aerogel into finer particles. In some embodiments, aflocculating agent may be added to the mixture in the mixing chamber602. In some embodiments, no flocculating agent may be included in thefiber reinforced nonwoven aerogel mat. The uniform mixture is thenprocessed into a trough collection system 604 and then processed onto aporous surface, such as a forming wire, on an incline conveyor 606 toremove water from the slurry mixture. Even without a flocculating agentor binder (the binder is added in a subsequent processing step), theentangled fiber in the mixture provides a network that can hold theaerogel particles and allow a wet laid mat to be formed on the formingwire. Similar to the system 200 described above with reference to FIG.2, the system 600 may include a whitewater recycler or whitewatercollector 620 that is fluidly coupled with the trough collection system604 and the mixing chamber 602. Because the nonwoven mat may not includeblack material opacifiers, such as carbon black, for cryogenic, cold, orwarm temperature applications, the whitewater removed from the mixturecan be recycled.

Because the mixture is processed immediately or soon after theingredients are mixed in the mixing chamber 602 so that the mixture donot settle or separate and create non-uniformity in the troughcollection system 604, the mixture collected on the incline conveyor 606may still contain at least 10% water content. The wet laid mixture isthen transferred to a binder application conveyor 608. A binderapplicator 610, such as a curtain coater, may be positioned above thebinder application conveyor 608 for applying a binder to the wet laidmixture. A vacuum table 612 may be positioned below the binderapplication conveyor 608 to suction the binder into the wet laid mat andremove excess binder liquid. The mixture is then sent to a drying/curingoven 614 via an oven conveyor 616 to produce a fiber reinforced nonwovenaerogel mat. Conveying the wet laid mixture from the incline conveyor606 to the binder application conveyor 608 and subsequently the ovenconveyor 616 may be done carefully to prevent wet laid mixtures withhigh aerogel content from separating and pulling apart. The dried/curednonwoven mat is then wound up or sheeted and stacked for secondaryprocessing.

The system 600 illustrated in FIG. 6 includes an open trough head box.In some embodiments, the system 600 may be equipped with a closed headbox, such as a low to medium pressure chamber into which the whitewatermixture is pumped and allowed to exit from a slot onto a forming wire.The exit includes a control slide, which may be a rectangular opening ofadjustable height. With a low pressure closed headbox, surfactants canbe added to the whitewater to create a froth or foam. Suspending theaerogel particles and fibers in this foam creates substantially uniformmixtures that can be evenly extruded onto or vacuumed onto the formingwire.

Although a wet laid process is described above, air laid or dry laidprocess may also be used in forming the fiber reinforced nonwovenaerogel mats. However, a wet laid process is generally faster than atypical dry laid process. The wet laid process described herein may takeonly 10% of the time a typical dry laid process requires.

With reference to FIG. 7, nonwoven mats with a non-uniform concentrationof aerogel particles across a thickness dimension of the nonwoven matmay be produced. In some embodiments, an aerogel rich upper surface canbe produced by sprinkling additional aerogel particles on the mat. Insome embodiments, the aerogel particles may be added at the same timethe binder is being applied onto the mat by a binder applicator 710. Insome embodiments, the aerogel particles may be applied before or afterthe binder application. A dry particle feeder 720 may be used tosprinkle additional aerogel particles on the mat. Depending on theapplication sequence, the aerogel particles feeder 720 may be positionedupstream or downstream of the binder applicator 710. When the aerogelparticles and the binder are applied concurrently, opposing air curtains730 may be used to blend or mix the additional aerogel particles and thebinder. The blended aerogel particles and binder are then curtain coatedon the top of the nonwoven mat and vacuum is used to suction the binderinto the mat and remove excess binder liquid. Other mixing or blendingmethods may be used so that the aerogel may not need to be suspended inthe binder and applied via the curtain coater.

The aerogel particles used for forming the nonwoven mat may includehydrophobic silica aerogel, but other particulate aerogels can be used.The aerogel particles may have a diameter ranging from 0.01 to 1.2 mm,such as Cabot P200 aerogel particles manufactured by Cabot Corporation,for forming to form up to about 60% by weight aerogel content nonwovenmats with good uniformity. In some embodiments, the aerogel particlesused may have a diameter ranging from 1.2 to 4.0 mm, such as Cabot P300aerogel particles manufactured by Cabot Corporation, for forming highaerogel content up to 80% by weight nonwoven mat. In some embodiments,mixtures of aerogel particles having a diameter from 0.01 to 1.2 mm andaerogel particles having a typical diameter from 1.2 to 4.0 mm may beused to create desired finished nonwoven mat properties. Aerogelparticles that have larger diameters and minimal fines does not tend toblind off the collection screen. Finer aerogel particles that haverelatively smaller diameters may increase the dewatering time for matsat basis weights of 100 gsm or more.

The fibers used for the nonwoven mats may include bicomponent fibers,glass fibers, and/or a mixture thereof. The bicomponent fibers arebonding fibers which may include bicomponent polyethylene sheath withpolyester core (PE/PET) fibers, such as uncrimped Trevira 255 or 276fibers, including TREVIRA® 276 1.7 dtex bright rd 6 mm. Trevira 276fibers may be used for forming the nonwoven mat because the core orabout 50% by weight of the fiber is composed of Trevira CS polyesterwhich has excellent fire resistance compared to regular polyester.Depending on the end use applications, flame spread of 25 or less fireresistance as measured by ASTM E84 can be beneficial. Other bicomponentfibers that provides good fire resistance may also be used. The PEsheath of the bicomponent fibers may be activated to bond the fibers andthe aerogel particles together. Specifically, the temperature of thedrying/curing oven 614 may be selected to activate the sheath of thebonding fiber, creating aggressive tacky adhesive that as it cools holdsthe fibers and the particulate matrix together. The temperature of thedrying/curing oven 614 may not be set too high so as to prevent thefibers from being exposed to excessive heat to minimize shrinkage. Thefinished nonwoven mats may be used for applications that are below theactivation temperature of the PE sheath, such as below or about 120° C.or about 248° F.

Higher application temperature may be achieved by using differentfibers, such as inorganic fibers. In some embodiments, the inorganicfibers may be added to the bicomponent fibers. Depending on theapplications, about 0 to 15% or 0 to 20% by weight of one or moreanother types of fibers can be added to provide desired properties. Insome embodiments, organic bicomponent fibers may be replaced entirely bythe inorganic fibers. The inorganic fibers may include glass fibers,such as coarse glass fibers, glass microfibers, or a mixture thereof.The glass fibers may constitute about 1% to 20% by weight of the curednonwoven mat. In some embodiments, the fibers used for forming thenonwoven mats may include coarse glass fibers only. The coarse glassfibers may constitute about 5%, about 10%, about 15%, or about 20% byweight of the cured nonwoven mat in various embodiments. The coarseglass fibers typically have an average fiber diameter between about 6 μmand about 13 μm. An exemplary glass fiber that can be used for producingthe nonwoven mat is available from Johns Manville as identified asSTRANGF.WM 8 μm/8 mm, which is easier to transfer, to weigh thequantity, and less expensive than glass microfibers. In someembodiments, the fibers used for forming the nonwoven mats may furtherinclude glass microfibers having an average fiber diameter between about0.5 μm and about 3 μm homogenously dispersed within the coarse glassfibers. The coarse glass fibers and the glass microfibers may eachconstitute about 1 to about 10% weight of the cured nonwoven mat.

In various embodiments, the binder for bonding the entangled fibernetwork and the aerogel particles embedded therein can be the sheathmaterial of the bicomponent fibers, another binder material added to themixture of fibers and aerogel particles, or a combination of thebicomponent fibers and a separate binder material. As the binder cures,the binder forms a binding framework that bonds the entangled fibers andthe aerogel particles together. When bicomponent fibers are used,addition of another liquid binder may be optional. In some embodiments,a binder of about 0.1% to about 15% by weight of the cured nonwoven matmay still be added to the nonwoven mat that uses bicomponent fibersbecause each of the combined binding components can provide uniqueprocessing benefits and/or finished product properties. For example, theliquid binders, once dried and cured, may provide more efficient bindingability by weight or high coverage by weight than bicomponent fibersgiven that bicomponent fibers may have large diameters. A bonded networkof bicomponent fibers may provide better tensile strength compared toliquid binders alone. Bicomponent fibers can be reactivated with heatwhen the nonwoven mat is mandrel wound up resulting in layer to layerbonding as will be described in more detail below. In some embodiments,when the bicomponent fibers are replaced by inorganic fibers, such asglass fibers, a liquid binder, such as polyvinyl alcohol (PVOH), ofabout 1% to about 10% by weight of the nonwoven mat may be used.

Additions of binder materials and/or fibers may decrease the overallaerogel content in the finished nonwoven mat, which may reduce thermalinsulation performance, and in some cases, proportionally. However,additions of fire resistant binder or glass fibers or other performanceenhancing components may be beneficial. In some embodiments, liquidbinders such as acrylic, melamine, or reactive silicone are suitablebinders for higher temperature applications up to the use temperaturelimit of the binder. In some embodiments, reactive silicone orfluoropolymer can be added to the binder to provide improved waterresistance of the finished nonwoven mat. The water resistive treatmentcan be done in-line as a secondary step by curtain coating, rollercoating, or spray application. The water repellant treatment can also bedone in an off-line application, drying and curing process.

Table 7 below provides exemplary compositions of the nonwoven mats.

TABLE 7 Exemplary compositions of fiber reinforced nonwoven aerogelmats. Example Composition 1 150 g PE/PET bicomponent 255 fiber and 220 gaerogel particles in whitewater, curtain coated with 18% (by weight ofcured mat) melamine binder to produce 2 mm thick mat at 120 gsm 2 150 gPE/PET bicomponent 255 fiber and 220 g aerogel particles in whitewater,no liquid binder, nonwoven blend heated to 135° C. to activate thebonding fiber and consolidate the aerogel particles to produce 2 mmthick mat at 120 gsm 3 63 g PE/PET bicomponent 276 fiber, 31 g of 8μglass fiber and 220 g of P300 aerogel particles in whitewater, no liquidbinder, nonwoven blend heated to 130° C. to activate the bonding fiberand consolidate the aerogel particles to produce 2 mm thick mat at 120gsm 4 63 g PE/PET bicomponent 276 fiber, 31 g of 8μ glass fiber and 220g of P300 aerogel particles in whitewater, no liquid binder, nonwovenblend heated to 130° C. to activate the bonding fiber and consolidatethe aerogel particles to produce 6 mm thick mat at 400 gsm 5 63 g PE/PETbicomponent 276 fiber, 15 g of 8μ glass fiber, 15 g of 0.8μ glass fiberand 220 g of P300 aerogel particles in whitewater, no liquid binder,nonwoven blend heated to 130° C. to activate the bonding fiber andconsolidate the aerogel particles to produce 6 mm thick mat at 400 gsm 655 g PE/PET bicomponent 276 fiber and 220 g of P300 aerogel particles inwhitewater, no liquid binder, nonwoven blend heated to 130° C. toactivate the bonding fiber and consolidate the aerogel particles toproduce 7 mm thick mat at 400 gsm 7 165 g WM 8/8 glass fibers with 330 gP200 aerogel particles in whitewater and then curtain coated with up to18% (by weight of cured mat) melamine binder to produce 2 mm thick matat 120 gsm 8 88 g WM 8/8 glass fibers with 330 g P300 aerogel particlesin whitewater and then curtain coated with 20.9 g or 5% (by weight ofcured mat) PVOH binder to produce 4.5 mm thick mat at 300 gsm

Depending on the equipment capabilities and limitations, nonwoven matsof different area weight, thicknesses, and/or densities may be achieved.Although the exemplary mats listed have area weight of 120 gsm, 300 gsm,or 400 gsm, the area weight of the nonwoven mats in various embodimentsmay range between about 100 gsm and about 500 gsm, between about 150 gsmand about 400 gsm, or between 200 gsm and about 300 gsm. The thicknessof the nonwoven mats produced may range between about 1 mm and about 10mm, such as greater than or about 1 mm, greater than or 2 mm, greaterthan or about 3 mm, greater than or about 4 mm, greater than or about 5mm, greater than or about 6 mm, greater than or about 7 mm, greater thanor about 8 mm, greater than or about 9 mm, or greater. In someembodiments, nonwoven mats with a thickness less than 1 mm or greaterthan 10 mm may also be produced. The density of the nonwoven matsproduced may range between about 4 pcf and about 5 pcf. Nonwoven matswith a density below 4 pcf or above 5 pcf can also be produced.

The nonwoven mat may include between about 50% and about 80% or betweenabout 60% and about 75% by weight aerogel content, and may include about55%, about 60%, about 65%, about 70%, about 75%, or greater by weightaerogel content. The nonwoven mat may include about 0% to about 30%,about 5% to about 25%, or about 10% to about 20% by weight bicomponentfiber content. The nonwoven mat may include about 0% to about 30%, about5% to about 25%, or about 10% to about 20% by weight inorganic fiber,such glass fiber content. The nonwoven mat may include about 0% to about15%, about 2% to about 12%, or about 5% to about 8% by weight bindercontent. For example, the nonwoven mat with the exemplary composition #8listed in Table 7 above includes about 75% aerogel particles, about 20%8 micron×8 mm glass fibers, and about 5% PVOH binder. The nonwoven matmay further include appropriate amount of other performance enhancingadditives, such as fire resisting, water repelling, and/or otheradditives.

The nonwoven mat delivers the desired thermal and acoustic properties.It is the inventor's belief that an aerogel to fiber ratio of 60:40 byweight deliver significant benefit. Raising the aerogel to fiber ratioto 70:30 yields even better thermal performance. Although certainexisting equipment may process a maximum aerogel to fiber ratio of80:20, higher or lower ratios may be pursued using different equipment.Examples 4 and 5 listed in Table 7 have an aerogel to fiber ratio of70:30, and have thermal and acoustic properties similar to existingaerogel blankets and have acceptable fire resistant properties. Examples4 and 5 are expected to provide flame spread of 25 or less fireresistance. In addition, with the binder, such as the bicomponent fiberand/or liquid binder, holding the aerogel particles together, thefinished nonwoven mat has good integrity and creates minimal dust duringhandling. Further, the processing of the bicomponent fibers iseco-friendly.

The nonwoven mat described herein can be further secondarily processedinto a wide variety of shapes and boards using molding, mandrel winding,or other suitable processing methods without destroying or decreasingany desired insulation and structural properties. Depending on theapplications, the secondarily processed insulation product may be in apipe form used for pipe insulation as discussed above with reference toFIG. 1. Other shapes and/or flat boards can also be produced through thesecondary processing, which can be particularly useful for applicationswhere excellent thermal performance is desired but space is constrained.The various secondary processing methods are not limited to processingthe nonwoven mats described herein, but may also be used to secondarilyprocess other thin layer aerogel insulation products.

In some embodiments, one or more layers of the nonwoven mat can bethermoformed into various shapes while the multiple layers of thenonwoven mat are bonded to each other as they take the shape of themold. Due to its thin profile and low thermal conductivity, a single,double, or more layers of the nonwoven mat may be molded into complexmolded shapes, which can be useful in managing heat transfer for a widevariety of electronics and other consumer goods. When multiple layers ofthe nonwoven mats are used, the mats may be the same as or differentfrom one another.

With reference to FIG. 8, in some embodiments, multiple rolls of thenonwoven mats 810 can be unrolled and combined together using anadhesive or using hot air or flame spray laminating process. Hot airknives 810 may be used to reactivate the sheath of the bicomponentfibers which bonds the multiple layers of the nonwoven mats 820 togetherto form a laminated insulation product 830. Although three rolls of thenonwoven mats 820 are shown in FIG. 8, less or more than three rolls ofthe nonwoven mats 820 may be bonded together to form the laminatedproduct 830. The rolls of the mats 820 may be the same or different fromeach other. Roller press may be employed to hold the mats together asthe reactivated bonding sheath bonds the mats together.

In some embodiments, instead of forming a flat board of insulationproduct, the nonwoven mat can be wound up on a mandrel, and heatlaminating may be used to laminate the layers as the mat is wound up.This would form a tubular insulation product, similar to the clamshellbody discussed above with reference to FIG. 1 above. The laminatedinsulation product may be faced or unfaced.

In some embodiments, the binder used for forming the nonwoven mat may bereactivated. For example, a polyvinyl alcohol (PVOH) binder may be usedfor forming the nonwoven mat. The PVOH binder may be subsequentlyreactivated by wetting the mat and heated to cure to bond multiplelayers of the nonwoven mats together.

In some embodiments, the nonwoven mat may be re-saturated with asecondary binder and stacked or layered up to form a desired insulationshape by molding, mandrel winding, or other suitable shaping techniques.FIG. 9 illustrates a method 900 of secondarily processing the fiberreinforced nonwoven aerogel mat into a finished product. The method 900may begin by forming fiber reinforced nonwoven aerogel mats at block905. At block 910, the nonwoven mats may be re-saturated with asecondary binder. Some exemplary secondary binders may include about 5to about 10% by dry weight sodium silicate or the polysiloxane binderfor molding the fiber reinforced aerogel composite discussed above withreference to FIGS. 2-5. The mats may be re-saturated with the secondarybinder by curtain coating, dipping the mats in the secondary binder, andother suitable techniques, depending on the thickness, density andporosity of the mat.

At block 915, multiple layers of the nonwoven mats re-saturated with thesecondary binder may be stacked together. The stacked layers may beplaced into a mold that molds the stacked layers into any suitableshapes. The mold also compress the stacked layers and thus increase thedensity of the multilayer product formed. In some embodiments, insteadof molding, the stacked layers may be wound around a mandrel to form acylindrical insulation product, which can be more economical processthan molding. In some embodiments, a single layer of re-saturatednonwoven mat may be wound around a mandrel multiple times to form thecylindrical insulation product. The mandrel pipe in some embodiments mayinclude holes for blowing hot air to facilitate the subsequentdrying/curing process.

At block 920, the secondary binder may be cured in an oven to bond themultiple layers of the nonwoven mats together. The drying and/or curingprocess may be performed at a temperature between about 350° F. to about400° F. for a period of time between about 30 minutes to about 3 hours,depending the secondary binder and/or the number of layers stacked. Atblock 925, the cured insulation product may then be trimmed to a desiredsize. Surface grinding and/or cleaning of may also be performed at block925, if necessary. In some embodiments, depending on the applications,the method 900 may further include applying a facer, such as aflame-retardant vapor barrier facer or similar jacketing, to the outersurface of the multilayer insulation product at block 930. A joining orsealing tape or other adhesives may also be applied along the edge ofthe outer facer at block 930. At block 935, the finished insulationproduct is packaged.

Depending on the desired thickness of the finished insulation product,the finished insulation product may include 2, 3, 4, 5, 6, 7, 8, 9, 10,or more layers of the nonwoven mats. The thickness of the finishedinsulation product may range between about 20 mm and about 100 mmdepending on the particular applications. The drying and/or curing timeincreases as the number of the nonwoven mat layers increases. Becausethe nonwoven mats, as well as the finished insulation product, possessexcellent insulation property, the number of layers of the mats stackedmay be determined by taking into account the drying/curing time involvedto maintain manufacturing efficiency. The finished products with athickness of ranging between about 5 mm and about 50 mm, formed from 2to 25 layers of the nonwoven mats having individual thickness of about 2mm, possess excellent structural and insulation properties. For example,a multi-layer finished product with a thickness of about 25 mm may beformed from about 9 layers of about 300 gsm aerogel containing nonwovenmat where the individual mat layers are re-saturated with a secondarybinder, layered up and cured into an insulation of about 25 mm thicknessunder compression.

The secondary binder is selected such that it provides good bonding,helps control and minimize dust, is fire retardant or inorganic so thatthe binder does not contribute to combustibility, is moisture and waterresistance, does not contain or generate toxic or hazardous componentsduring manufacturing or using the finished insulation product, and doesnot deteriorate or degrade with time or with exposure to approved usetemperatures. A secondary binder that provides excellent bonding, fireresistance, water repellency, and is suitable for use at exposuretemperatures as low as −423° F. and up to 900° F. may be obtained bymixing a polysiloxane binder, such as Polon MF-56 manufactured byShin-Etsu Silicones of America, and a reactive silicone water repellent,such as SF 75 manufactured by Dow Corning, together in a dilute aqueoussolution to generate a uniform mixture of blend. Depending on theapplication, the dry weight ratio of polysiloxane binder to the reactivesilicone water repellent for forming the secondary binder may be atleast about 5:1, at least about 10:1, at least about 15:1, at leastabout 20:1, or greater. In some embodiments, about 9.44 parts by dryweight of polysiloxane binder and about 0.66 parts by dry weight ofreactive silicone water repellent may be mixed in the dilute aqueoussolution. The diluted mixture is then infused into the nonwoven mat bydip saturation and nip compression to dewater, by curtain coating andvacuum dewatering, or other suitable process. The dilution and/orsaturation process is selected so that the finished cured product has atleast about 4% and no more than about 20% by dry weight secondary bindercontent.

As discussed above, the nonwoven mat includes a first binder, e.g.,bicomponent fibers and/or a liquid binder, that forms a bindingframework and bonds the entangled fibers and aerogel particles together.When the mats are saturated with the secondary binder, the secondarybinder is dispersed throughout each mat. Consequently, when the multiplelayers of the mats are stacked together, the secondary binder formsanother or a second binding framework and bonds the layers together bybonding everything within the layers and between the layers.

Because the individual mats may be secondarily processed into a finishedproduct with improved structural integrity, the binder used for formingthe individual mats may only need to provide the individual nonwoven matwith sufficient structural strength for handling in the subsequentsecondary processing, such as running through a deep saturator, windingup around the mandrels, placing into molds, etc. Accordingly, theindividual mats may be formed without a drying/curing process, and canbe immediately secondarily processed after the mats have been laid,which may improve overall throughput. Because the binder for forming thenonwoven mats has not been cured, the process of re-saturating the matswith a secondary binder may also be omitted. The binder used for formingeach individual mat is cured to bond the multiple layers together.

Depending on the secondary process utilized, the aerogel content of themulti-layered or laminated mats may change. The initial or individualaerogel nonwoven mat may contain about 65% to about 80%, such as 75%,aerogel particles. When the nonwoven mats are infused with the secondarybinder and cured, the aerogel content in the resulting product may bereduced. The resulting product may contain about 5% or about 10% lessaerogel content as compared to the nonwoven mats. Accordingly, theresulting product may contain about 50% to about 75% aerogel content,and more commonly, about 65% aerogel content. When molded and densifiedinto shapes, the finished multi-layered or laminated product has thermalperformance equivalent to the molded fiber reinforced aerogel compositeproduct described above with reference to FIGS. 2 to 5. Although theaerogel content may change in the secondarily processed insulationproduct, the distribution of the aerogel particles in the secondarilyprocessed insulation product may be similar. For example, if the aerogelparticles are substantially uniformly distributed throughout thenonwoven mat, then the aerogel particles are also substantiallyuniformly distributed throughout the secondarily processed product. Ifthe concentration of the aerogel particles are not uniform in thenonwoven mat, such as the nonwoven mat discussed above with reference toFIG. 7 which includes a aerogel rich top surface, then secondarilyprocessed product may also include a non-uniform or varyingconcentration of aerogel particles across a thickness dimension of thefinished product, with the concentration of the aerogel particles beinghigher at the interface of the multiple layers than elsewhere in thefinished product. In some embodiments, variation of the aerogelconcentration in the finished product may be achieved using nonwovenmats having uniform aerogel particle distribution but different levelsor concentrations of aerogel particles.

Because the second binder is dispersed within and throughout eachnonwoven mat, if the stacked layers are compressed, then the compressedform will be maintained once the second binder cures, which results in amultilayer insulation product with an increased density. Consequently,the secondary processing allows low density aerogel nonwoven mats to bereadily made through an air laid or wet laid process and then processedinto higher density insulation product that can be used for, e.g., pipeinsulation. The aerogel nonwoven mats formed using an air laid or wetlaid process may have a density of below or about 5 pcf. The density ofthe secondarily processed product may range between about 5.5 pcf andabout 9 pcf, between about 6 pcf and about 8 pcf, or between about 6.5pcf and about 7.5 pcf. A density that is greater than 9 pcf may also beachieved. Increasing the density from below or about 5 pcf to about orabove 6 pcf delivers optimized thermal performance, excellent insulationintegrity, durability, and compression resistance that can be tailoredto meet a wide variety of applications. However, it has been observed bythe inventor that when the density increases beyond 10 pcf, the thermalperformance of the finished product for cryogenic applications maydecrease as the density continues to increase. A ratio of the density ofthe finished insulation product to the density of the individualnonwoven mat may range between about 1.2:1 and about 2:1, and may beabout 1.6:1 in some embodiments. The density of the finished insulationproduct may be greater than the density of the nonwoven mats by at leastabout 20%, at least about 40%, at least about 60%, at least about 80%,at least about 100%, or greater.

Typically, the initial or individual aerogel nonwoven mat may have athickness of about 1 mm to about 10 mm. The thickness of each layerafter the secondary processing may be reduced by at least or about 1%,at least or about 3%, at least or about 5%, at least or about 10%, atleast or about 15%, at least or about 20%, at least or about 25%, atleast or about 30%, at least or about 40%, at least or about 50%, orgreater.

While several embodiments and arrangements of various components aredescribed herein, it should be understood that the various componentsand/or combination of components described in the various embodimentsmay be modified, rearranged, changed, adjusted, and the like. Forexample, the arrangement of components in any of the describedembodiments may be adjusted or rearranged and/or the various describedcomponents may be employed in any of the embodiments in which they arenot currently described or employed. As such, it should be realized thatthe various embodiments are not limited to the specific arrangementand/or component structures described herein.

In addition, it is to be understood that any workable combination of thefeatures and elements disclosed herein is also considered to bedisclosed. Additionally, any time a feature is not discussed with regardin an embodiment in this disclosure, a person of skill in the art ishereby put on notice that some embodiments of the invention mayimplicitly and specifically exclude such features, thereby providingsupport for negative claim limitations.

Having described several embodiments, it will be recognized by those ofskill in the art that various modifications, alternative constructions,and equivalents may be used without departing from the spirit of theinvention. Additionally, a number of well-known processes and elementshave not been described in order to avoid unnecessarily obscuring thepresent invention. Accordingly, the above description should not betaken as limiting the scope of the invention.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimits of that range is also specifically disclosed. Each smaller rangebetween any stated value or intervening value in a stated range and anyother stated or intervening value in that stated range is encompassed.The upper and lower limits of these smaller ranges may independently beincluded or excluded in the range, and each range where either, neitheror both limits are included in the smaller ranges is also encompassedwithin the invention, subject to any specifically excluded limit in thestated range. Where the stated range includes one or both of the limits,ranges excluding either or both of those included limits are alsoincluded.

As used herein and in the appended claims, the singular forms “a”, “an”,and “the” include plural referents unless the context clearly dictatesotherwise. Thus, for example, reference to “a process” includes aplurality of such processes and reference to “the device” includesreference to one or more devices and equivalents thereof known to thoseskilled in the art, and so forth.

Also, the words “comprise,” “comprising,” “include,” “including,” and“includes” when used in this specification and in the following claimsare intended to specify the presence of stated features, integers,components, or steps, but they do not preclude the presence or additionof one or more other features, integers, components, steps, acts, orgroups.

What is claimed is:
 1. A pipe insulation product having a curved innersurface and a curved outer surface that enables the pipe insulationproduct to be fit about a pipe to be insulated, the pipe insulationproduct comprising: coarse glass fibers having an average fiber diameterbetween about 8 μm and about 20 μm; glass microfibers having an averagefiber diameter between about 0.5 μm and about 3 μm; aerogel particles;and a binder that bonds the coarse glass fibers, the glass microfibers,and the aerogel particles together to form a fiber reinforced aerogelcomposite; wherein the coarse glass fibers, the glass microfibers, theaerogel particles, and the binder are uniformly dispersed in the pipeinsulation product; and wherein the fiber reinforced aerogel compositeincludes between about 50 wt. % and about 75 wt. % of the aerogelparticles.
 2. The pipe insulation product of claim 1, wherein the fiberreinforced aerogel composite includes about 3 wt. % of the coarse glassfibers and about 10 wt. % of the glass microfibers.
 3. The pipeinsulation product of claim 1, wherein the fiber reinforced aerogelcomposite has a density of between about 6 pcf and about 8 pcf.
 4. Thepipe insulation product of claim 1, wherein the fiber reinforced aerogelcomposite further comprises scrap particles of the fiber reinforcedaerogel composite, wherein the scrap particles have a diameter of lessthan or about 0.13 inches.
 5. The pipe insulation product of claim 4,wherein the scrap particles have a diameter of less than or about 0.1inches.
 6. The pipe insulation product of claim 4, wherein a ratio of acombined weight of the coarse glass fibers, the glass microfibers, theaerogel particles, and the binder to a weight of the scrap particles ofthe fiber reinforced aerogel composite is about 10:1 or greater.
 7. Thepipe insulation product of claim 1, wherein the fiber reinforced aerogelcomposite further comprises an inner facer attached to the curved innersurface of the fiber reinforced aerogel composite and an outer facerattached to the curved outer surface of the fiber reinforced aerogelcomposite body.
 8. The pipe insulation product of claim 7, wherein theinner facer is a spunbond, a scrim, or a woven or nonwoven porous layer.9. The pipe insulation product of claim 7, wherein the outer facer is avapor barrier.
 10. The pipe insulation product of claim 1, wherein anaverage diameter of the aerogel particles is between about 10 nm andabout 4.0 mm.
 11. The pipe insulation product of claim 1, wherein theaerogel particles comprise silica aerogel.
 12. The pipe insulationproduct of claim 1, wherein the fiber reinforced aerogel composite has athickness of between about 1 inch and about 1.25 inches.
 13. A pipeinsulation product comprising: coarse fibers having an average fiberdiameter of greater than 6 microns; microfibers having an average fiberdiameter of less than 6 microns; aerogel particles; and a binder thatbonds the coarse fibers, the microfibers, and the aerogel particlestogether to form a fiber reinforced aerogel composite; wherein a ratioof a weight of the aerogel particles and a combined weight of the coarsefibers and the microfibers is between about 2:1 and about 5:1.
 14. Thepipe insulation product of claim 13, wherein the fiber reinforcedaerogel composite includes between about 50 wt. % and about 75 wt. % ofthe aerogel particles.
 15. The pipe insulation product of claim 13,wherein a ratio of a weight of the coarse fibers to a weight of themicrofibers is about 3:10.
 16. The pipe insulation product of claim 13,wherein the coarse fibers, the microfibers, the aerogel particles, andthe binder are uniformly dispersed in the pipe insulation product. 17.The pipe insulation product of claim 13, wherein the fiber reinforcedaerogel comprises at least one of the following facers: an inner facerattached to an surface of the fiber reinforced aerogel composite; or anouter facer attached to an outer surface of the fiber reinforced aerogelcomposite body.
 18. The pipe insulation product of claim 13, wherein thefiber reinforced aerogel composite includes about 3 wt. % of the coarsefibers and about 10 wt. % of the microfibers.
 19. The pipe insulationproduct of claim 13, wherein the fiber reinforced aerogel compositefurther comprises scrap particles of the fiber reinforced aerogelcomposite, wherein the scrap particles have a diameter of less than orabout 0.13 inches.
 20. The pipe insulation product of claim 13, whereincoarse fibers include glass fibers, the microfibers include glassfibers, and the aerogel particles comprise silica aerogel.